steinmbtz



(No Model.) C.' P. STEINMETZ.

SGRBW CUTTING GBUGK.

No. 283,679. Patented Aug. 21, 188s,

'L "15" 8 5 1'. S Y L UNITED STATES PATENI Fries..

GASPAR FR'. STEINMETZ, PORT CHESTER, NEWT YORK.

SCREW-CUTTING CHUCK.

SPECIFCATION forming of Port Chester, in the county of 'lVestchester and State of New York, have invented certain' new and useful improvements in Screw-Cutting Qhucks, of which the following is aspecification.

This invention has reference to an improved chuck for cutting screw-threads of different lengths ,on bolts of. different sizes,the chuck having the advantage-of beingfmore durable than the screw-cutting dies heretofore'in use,l

so as to dispense with the frequent changing and retempering of the dies.

The invention consists .ofY a thread-'cutting chuck provided with four segmental threadeutting dies, each of which is rigidly secured to a-spindle the axis of which is placed at a suitable oblique angle of inclination to the central axis of the chuck, according to the number of threads per inch to be cut by the chuck. Eachfspindle is secured to a supporting-socket, that turns in the rear portion of the chuck, and is provided at its rear end with a roundedoff andspring-pressed .crank-arm, that is enga-ged by the' conical end of a longi` tndinally-movable spindle, by which the dies are set to the proper thickness of the bolt to be threaded.

In the accompanying drawings, Figure l represents a side elevation, partly in section, of my improved screw-cutting chuck. Fig. 2 is a front-elevation'. Fig. 3 is a vertical transverse section on line .c ai, Fig.v l, and Fig. Il is a rear elevation of the same.

Similarletters of reference indicate correspending parts.

' of two cylindrical main parts, A A', that areV My improved thread-cuttin g chuck is made connected by longitudinal screw-bolts o o. The front part, A, is arranged with inclined cylindrical socket-holes equidistantly from thecentral axis, for snpportingfour spindles, B B,

' left-hand screw-threads are to be cut, so as to prevent the working loose of the cuttingdies C C. The heads ofthe fastening-screws C are at their cutting-edges.

' iconntersunk into the'dies C, the latter having at the bottom a collar, c, that is set into a socket-recess, a', at the front ends of the spindles B B, so that a rigid connection ofthe spindle with the dies is secured. The spindles VB B are also provided with shoulders or offsets b, that rest in corresponding recesses, b,.of the socket-holes of the main part A. Thel spindles B B and their socket-holes are set at such an angle of inclination to the central axis ofthe chuck (said angle of inclination being `in proportion to the number of threads per inch, and made greater when aless number of threads is required, and smaller when agreater number of threads per inch is to be out) that the proper pitch of the threads is obtained by the cutting-dies. The segmental dies C are made oi' tempered steel and screwthreaded at their circumi'erences. They can be used for a considerable length of time before they are entirely wornout, they being sharpened over and over again at their edges as they become dull, until the entire body of the same is used up. They are for this purpose detached from their 'spindles by loosening the fastening-screws C C and sharpened In replacing the dies C C they are so secured'to their spindles that their sharpened edges are equidistant from the axis and project somewhat beyond the bolt-y gui'de hole at the center of the chuck, as shown in Fig. 2. The dies C C are then tightly clamped again by their fastening-screws C C. The rear ends of the spindles B B are also provided either with left -hand or right-hand threads, according as right-hand or left-hand threads are to be cut on the bolts, and screwed into sockets D, which turn by shoulders e ein inclined'guide-recesses at the rear end of the front part, A, while the sockets themselves are iitted into socket-holes ofthe rear part, A',

of the chuck, as shown clearly in Fig. l. The

sockets D are retained by their shoulders e e vinproper position in the parts A A. They are further provided at their rear ends with fixed rounded-off crank-arms D', which are acted upon at one side by springs ff, that are interposed between recesses f of the crank-arms D and an exterior retaining shell or band, f2. The crank-arms D are kept by the springs f f in contact with the conically-tapering end of a spindle, E. The forward movement of the spindle projects the tapered end thereof between the crank-arms D and swings them outward, thereby turning the several spindles 5 of the cutting-dies, so as to bring and hold the cutting-edges of said dies in contact with the bolt to be threaded, as shown in Fig. 2. When the spindle is retracted, the springs -f push in the crank-arms and turn the spindles of the 1o cutting-dies in the direction which causes the dies to open and release the bolt. rIhe direction of rotation indicated by the arrows l in Fig. 2 corresponds with that indicated `by the arrows 2, Fig. 3. The forward or backward motion of the spindle Ein the revolving shaft of the screwcutting chuck is accomplished by a machine for cutting screw-threads on bolts, which forms the subject-matter of a separate application filed at the same time 2o herewith. rI'he rear part, A, is secured to a hollow shaft, E, within which the spindle E operates, and by which shaft E rotary motion is imparted to the chuck for cutting the threads. According to the extent of forward or backy 2 5 ward motion of the spindle Efbolts of greateror less thickness can be introduced between the cutting-edges of the dies, which are then threaded by the turning of the chuck, and thereby gradually drawn into the central opening in the front part, A. Asthe partsA A are rigidly connected to each other by the longitudinal screw-bolts o o, all the actuating parts of the chuck are retained by the parts A A, which are also properly lubricated, so 3 5 as to produce the smooth working of the spindles in their bearings. The cutting-dies are set into corresponding face-recesses a2 of the front part, A, as shown clearly in Fig. 2. Sep,-

arate cutting-chucks have to be constructed for 4o the varying pitch of the threads, as the angle of inclination ofthe die-spindles is determined by the pitch of the threads.. Each size of-chuck serves for cutting bolts of certain sizes, larger sizes of bolts requiring also larger chucks and 4 5 dies.

The advantages of my improved screw-cutting chuck are, first, that the solid. segmental dies can be re-sharpencd a great number of as new and desire to secure by Letters Patenttimes until the entire body of the same is worn out, whereby the chuck is serviceable for a much greater length of time than the screw-cutting dies heretofore in use 5 secondly, that bolts of different sizes can be threaded to different lengths of thread by the same chuck; and thirdly, that a considerable savin gin time and labor is obtained, as the retempering and resetting of the dies heretofore in use is entirely dispensed with.

Having thus described my invention, I claim y parts A A', having longitudinal center opening and inclined socket-holes, die-spindles B B, having fixed segmental cutting-dies C C, said spindles being set at an angle of inclination to the axis of the chuck, a longitudinallysliding spindle, E, having a tapering end, and means whereby the spindles and cutting-dies are set to the proper thickness of bolts by the central spindle, substantially as specified.A

3. In a screw-cutting chuck, the combination Aof connected main parts A A, inclined die-spindles B B, cutting-dies C C, fasteningscrews C G, socket-pieces D D, having curved crank-arms D D', springsff, retaining-band f2, and longitudinal]y-sliding center spindle, E, having tapering front end engaging the cranks, substantially as described.

In testimony that I `claim the foregoing as 9o my invention I have signed my nan1e in presf ence of two subscribing witnesses.v

GASPAR FR. STEINMETZJ Vitnesses:

CARL Kinr, SIDNEY MANN.r 

